There's many things that can cause incontinence. For a doctor to say you might have this or this or this, that would still only be speculation. That's why tests are performed to eliminate other possibilities. Just be patient, let them narrow down the culprits and give you a more accurate diagnosis rather than a guess.

The ultrasound is standard. Like the others have said. They will have you pee, then use it to see how much pee might be left over in your bladder. Anywhere from 1 to 30 millaliters is completely normal, more than that can indicate retention.

Like almost everyone has said a ultrasound is completely standard (especially if you have any other medical issues that can be playing along). They like to rule out anything they can even if they think it will be a complete long shot (I find one less possibility is always good). They also like to see what your urinary system looks like so they, know how much your bladder can hold for when and if they do a voiding study, or to see if there is something wrong physically (which I do not think is often), or you just have a smaller than average sized bladder (agin I do not think this is often the case).